Glacier changes and their causes in Noijin Kangsang Region,Xizang,China
Noijin Kangsang Region is one of the primary distribution areas of extremely high-altitude glaciers in the mountainous region of southern Xizang (Tibet). It is situated adjacent to the 349 national highway from Lha-sa to Shigatse. The status and changes of glaciers in this Region are of wide concern. Assessing the glacier changes in the region is of great significance for guiding local glacier development,as well as for monitoring and protection. Based on the remote sensing images of the historical period,the glacier boundary of Noijin Kang-sang Region from 1976 to 2022 was extracted by using the band ratio and visual interpretation method. The char-acteristics of glacier area,surface velocity and thickness change in Noijin Kangsang Region were analyzed as a whole,and three typical glaciers in the region were selected for detailed analysis. Combined with factors such as climate,topography and glacier surface albedo,the reasons for glacier changes are explained. The results show that:From 1976 to 2022,the glacier area in Noijin Kangsang Region decreased by (17.88±6.75) km2,it ac-counted for (17.63±6.70)％ of the glacier area in 1976. There are significant differences in the number and area changes of glaciers of different sizes,and the topographic characteristics of glaciers also lead to the heterogeneity of glacier changes. From 2000 to 2019,the average thinning rate of glaciers in Noijin Kangsang Region was 0.26 m·a-1. Glacier thinning was most prominent during 2000—2004. In recent years,the thinning amount and thinning range of regional glaciers have shown a downward trend. From 1988 to 2018,about 62％ of the glacier-covered areas in Noijin Kangsang Region showed a deceleration trend. Within the region,eight glaciers have shown significant acceleration,with topography being the primary driving factor for glacier acceleration,while the increase in liquid precipitation at high altitudes may be a major contributing cause to the acceleration. From 1968 to 2022,the three typical glaciers all showed a state of retreat,but the retreat,thinning and surface veloci-ty changes of typical glaciers in different periods had distinctive characteristics. The warming of Noijin Kang-sang Region in the past 20～30 years is the main reason for the retreat of glaciers,and the topography affects the retreat,thinning and surface velocity changes of regional glaciers. Simultaneously,the reduction in glacier sur-face albedo is also one of the reasons driving glacier melting.
glacier changeglacier velocityclimate changeglacier albedotopographic featureNoijin Kangsang Region
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NSTL
万方数据
